Thanks to nine ancient men and women with poor oral hygiene, researchers have determined that foragers in the Balkans 8,600 years ago were cheating on their wild diets by supplementing them with domesticated cereals.

A look at the starch remains entrapped in the calcified dental plaque of human teeth gathered from a dig site in the central Balkans suggest that wheat and barley reached these foragers at least four centuries earlier than previously thought.

"The deposition of mineralised plaque ends with the death of the individual,” explains Emanuela Cristiani from The McDonald Institute for Archaeological Research, University of Cambridge, in a press release. That means ancient dental plaque seals a record of dietary preferences during given periods in human history.

To figure out who was eating what, and when, the researchers compared the plaque content of the forager teeth to that of three women who belonged to an early farming community nearby.

Wedged between the hunting and gathering of the Paleolithic and the farming explosion of the Neolithic sat the Mesolithic period — some continued to practice intensive hunting during this time, while others were slowly making the transition to agriculture.

The researchers argue that inland Mesolithic foragers likely had trade networks that extended into the earliest farming circles, and these avenues of exchange may account for the addition of “exotic” early domesticated crops to the foragers’ usual fare of wild oats, peas, beans, and grasses.

According to Cristiani, the microfossils trapped in dental calculus “reveal that domesticated plants were introduced to the Balkans independently from the rest of Neolithic novelties such as domesticated animals and artefacts, which accompanied the arrival of farming communities in the region."

The findings were published in the Proceedings of the National Academy of Sciences.